How to Change the Time on Your Computer (Windows, Mac & More)

Getting the time wrong on your computer is more than a minor annoyance. It can break email timestamps, mess up file versioning, trigger security certificate errors, and even prevent software from authenticating properly. Knowing how to change it — and understanding why the settings behave the way they do — puts you back in control.

Why Your Computer's Clock Matters More Than You Think

Your operating system uses the system clock for almost everything running in the background: scheduling updates, timestamping documents, syncing with servers, and validating SSL certificates when you visit websites. If your clock drifts far enough off, browsers may block secure sites entirely, and cloud services can refuse to sync.

The clock also interacts with your time zone setting and, separately, with daylight saving time (DST) adjustments. These are three distinct values — the raw time, the time zone offset, and DST rules — and getting all three right is what makes your displayed time accurate.

How to Change the Time on Windows

Windows 10 and Windows 11

1. Right-click the clock in the bottom-right corner of the taskbar.
2. Select "Adjust date/time."
3. In the Settings window that opens, you'll see a toggle for "Set time automatically."

If that toggle is on, Windows is syncing with an internet time server (typically time.windows.com). You cannot manually edit the time while this is enabled — you'll need to turn it off first.

Once automatic sync is off:

• Click "Change" under Set the date and time manually
• Enter the correct date and time and confirm

To also fix your time zone, scroll down in the same Settings screen and either enable Set time zone automatically or choose your zone from the dropdown.

🕐 Pro tip: If your clock keeps resetting to the wrong time after you change it, the issue is often the CMOS battery — a small coin-cell battery on your motherboard that maintains the hardware clock when the computer is off. A dead CMOS battery means your system loses time every time it powers down.

Older Windows Versions (Windows 7 / 8)

Right-click the taskbar clock → "Adjust date/time" → click "Change date and time" → enter the correct values. The logic is the same; the interface is just slightly different.

How to Change the Time on a Mac

1. Click the Apple menu (top-left corner) → System Settings (macOS Ventura and later) or System Preferences (older macOS).
2. Go to General → Date & Time (Ventura+) or directly to Date & Time.
3. If "Set date and time automatically" is checked, the Mac is syncing with Apple's time servers. Uncheck it to edit manually.
4. Click the clock display, enter the correct time, and confirm.

macOS also separates time zone settings. If your Mac shows the right time but in the wrong zone, go to the Time Zone tab and either enable automatic detection (which uses location services) or set it manually from the map.

Linux: Changing the Time from the Terminal

On most Linux distributions, the system time is managed by systemd. The key command is:

timedatectl 

Running it with no arguments shows your current time, time zone, and whether NTP (Network Time Protocol) sync is active.

To set the time manually:

sudo timedatectl set-ntp false sudo timedatectl set-time "YYYY-MM-DD HH:MM:SS" 

To re-enable automatic sync:

sudo timedatectl set-ntp true 

Graphical Linux environments (GNOME, KDE) also expose these settings in their system preferences panels, so terminal access isn't always required.

Automatic Sync vs. Manual: What's the Difference?

NTP (Network Time Protocol) is the standard protocol that keeps internet-connected computers synchronized to within milliseconds of global reference clocks. For everyday use, leaving automatic sync enabled is almost always the right call — the OS handles corrections silently in the background.

Common Reasons the Clock Keeps Showing the Wrong Time

• 🔋 Dead CMOS battery — common on older desktops and laptops; the hardware clock resets on every power cycle
• Incorrect time zone — the raw time is right, but the displayed time is off because the zone is wrong
• DST rule mismatch — can happen on outdated OS installations that haven't received updated DST rules
• NTP server blocked — corporate networks or strict firewalls sometimes block time server traffic
• Dual-boot conflicts — Windows and Linux handle the hardware clock differently (local time vs. UTC), which can cause each OS to "correct" the time in opposite directions

The Variables That Shape Your Situation

What makes this seemingly simple task more layered than it looks:

• Operating system version — the menus and toggle locations differ across Windows 10, 11, macOS Monterey, Ventura, and various Linux distros
• Network environment — NTP sync requires outbound access to time servers on UDP port 123, which may be blocked in managed enterprise environments
• Hardware age — older machines are more likely to have failing CMOS batteries
• Dual-boot setups — require additional configuration to avoid OS conflicts over the hardware clock
• Virtualized systems — VMs typically sync time from the host machine, and the guest OS settings may be overridden

Whether you're fixing a one-time drift, dealing with a recurring reset, or configuring a machine that needs to stay precisely synced in a specific time zone, the right approach depends on which of these factors actually applies to your setup.